A rock outcrop dubbed 'Missoula,' near Marias Pass on Mars, is seen in this image mosaic taken by NASA's Curiosity rover. Pale mudstone (bottom of outcrop) meets coarser sandstone (top) in this geological contact zone.

A rock fragment dubbed 'Lamoose' is shown in this picture taken by NASA's Curiosity rover. Like other nearby rocks in a portion of the 'Marias Pass' area of Mt. Sharp, Mars, it has unusually high concentrations of silica.

This single frame from a sequence of six images of an animation shows sunspots as viewed by NASA's Curiosity Mars rover from April 4 to April 15, 2015. From Mars, the rover was in position to see the opposite side of the sun.

This single frame from a sequence of images shows sunspots as viewed by NASA's Curiosity Mars rover from June 27 to July 8, 2015; the rover was in position to see the opposite side of the sun from the side facing Earth during this period.

This 360-degree panorama from the Navigation Camera (Navcam) on NASA's Curiosity Mars rover shows the surroundings of a site on lower Mount Sharp where the rover spent its 1,000th Martian day, or sol, on Mars.

This 3-D stereo view from NASA's Curiosity Mars rover shows a 360-degree panorama around the location where the rover spent its 1,000th Martian day, or sol, on Mars. The site is a valley just below 'Marias Pass' on lower Mount Sharp.

The Martian outcrop where pale rock meets darker overlying rock near the middle of this view from NASA's Curiosity Mars rover is an example of a geological contact. It was taken with the rover's Navcam on May 21, 2015.

This view southeastward from NASA's Curiosity's Mastcam shows terrain judged difficult for traversing between the rover and an outcrop in the middle distance where a pale rock unit meets a darker rock unit above it.

This frame is from sequence of views NASA's Curiosity Mars rover recorded of the sun setting at the close of the mission's 956th Martian day, or sol (April 15, 2015), from the rover's location in Gale Crater.

This map shows the route on lower Mount Sharp that NASA's Curiosity followed in April and early May 2015, in the context of the surrounding terrain. Numbers along the route identify the sol, or Martian day, on which it completed the drive.

A sweeping panorama combining 33 telephoto images into one Martian vista presents details of several types of terrain visible on Mount Sharp from a location along the route of NASA's Curiosity Mars rover.

NASA's Curiosity Mars rover used its Navigation Camera (Navcam) to capture this scene toward the west just after completing a drive that took the mission's total driving distance past 10 kilometers (6.214 miles).

This stereo view from the Navigation Camera (Navcam) on NASA's Curiosity Mars rover shows the terrain ahead of the rover as it makes its way westward through a valley called "Artist's Drive." 3-D glasses are need to view this image.